Guidelines & Tools Emissions Factors Toolkit Published 2024 Share SHARE Facebook share Twitter LinkedIn Copy URL Email Download Download emissions-factors-toolkit en Added on: 11 April, 2025 Breadcrumb Home Resource Library Emissions Factors Toolkit The Emissions Factors Toolkit (EFT) is published by Defra and the Devolved Administrations to assist local authorities in carrying out Review and Assessment of local air quality as part of their duties under the Environment Act 1995 as amended by the Environment Act 2021.The EFT allows users to calculate road vehicle pollutant emission rates for NOx, PM10, PM2.5 and CO2 for a specified year, road type, vehicle speed and vehicle fleet composition.The EFT is updated periodically due to updates to underlying data including vehicle fleet composition and emissions factors. Users are therefore advised to check this page regularly to ensure they are using the most up to date version of the tool for their studies.